Motor vehicle crash events are serious matters for the safety of occupants because of the large decelerations and forces that may act on occupants during the crash. To minimize the consequences to occupants in a crash, vehicles are engineered to keep the accelerations and forces experienced by occupants during a crash as low as possible. Seat belts and supplemental restraint systems (air bags) are some of the devices that are utilized. How the vehicle crushes and absorbs energy in a crash is another factor influencing the forces and accelerations to which occupants are subjected. For example, a vehicle has inherent crush or collapse characteristics of its various structural components which serve as crash energy management structures to dissipate energy in the event of a crash.
Driveline components are often required to incorporate a means of axial collapse and energy absorption during a crash event in which the driveline system is impacted by a high axial force. In order to maintain underbody vehicle integrity in such an incident, conventional means of handling this axial load is to design an axial collapsing feature in the propeller (drive) shaft. FIG. 1 depicts a portion of a conventional driveline 10 which includes a collapse feature 12 of a propeller shaft 14. The axial collapse feature 12 is in the form of a reduced diameter section 18 having a swage interface 16 with a large diameter section 20 of the propeller shaft 14, wherein the propeller shaft, including the reduced and large diameter sections, is in the form of a hollow tube. A stud shaft 22 from a housing (of the transmission, transfer case, constant velocity joint, etc.) 24 is connected, as for example by welding, to an end cap 26 of the propeller shaft 14. In the event of a crash, the propeller shaft 14 breaks at the swage interface 16, allowing the reduced diameter section 18 to slidingly telescope into the interior space of the large diameter section 20.
While a propeller shaft swage interface is the standard practice for providing a propeller shaft axial collapse function, it has several disadvantages, including swaging expense, increased propeller shaft assembly run-out, and underbody accommodation for two diameter sections of the propeller shaft. Accordingly, what remains needed in the art is a propeller shaft axial collapse capability which does not rely upon conventional swaging of the propeller shaft.